Patent GB-748828-A (GB)
Title: Firing mechanism for firearms
IPC: F41A19/33
Filed: 1953-07-13
Abstract: 748,828. Automatic fireanns. INSTITUTO NACIONAL DE INDUSTRIAL, and RUF. L. V. July 13, 1953, No. 19397/53. Class 92 In an automatic firearm adapted to fire single shots, the breech contains a live cartridge and is closed in the cocked position for single shot firing and is open and empty in the cocked position for continuous fire, the firing mechanism including a nivoted sear 10a, Fig. 3 for use in single shot firing and a pivoted sear 6 Fig. 4 for use in continuous fire. a cocking and actuating lever 15 for the sear 10a being pivotally mounted or the trigger 13 and is arranged, for single shot firing, to project into the recoil path of the breech block 7 to automatically recock the sear 10a even though the trigger remains pulled and for continuous fire to be pivoted out of the path of the breech block, a control cam 4 being movable to three positions corresponding to single shot firing. safe and continuous fire. The breech block comprises the breech block proper 7a carried in an outer casing 7<SP>1</SP> by means of a helix, the outer casing 7<SP>1</SP> reciprocating between straight parallel guides in the breech casing under the action of a gas operated plunger 18 and return spring 9. When the casing 7<SP>1</SP> is urged to the right. Fig. 3, it moves relative to the breech block 7a causing partial rotation thereof to release shoulders 7b of the breech block from recesses 7c in the breech, the breech block 7a then moving back with the casing 7<SP>1</SP> as shown in Fig 4. On closing the breech the reverse procedure occurs. In the cocked position for firing single shots, Fig. 3, the firing pin 11 is held back by the sear 10a engaging a put 8 and the sear 6. pivoted at 22, is withdrawn downwards against a return spring 23 from engagement with the breech block casing 7' by a surface 4g on the cam 4 pressing upwards against the arcuate edge 6a of the sear 6. The cocking lever 15. Figs. 3. 5 is of forked formation and an actuating lever 14 is housed between the forks both being pivoted at 16 to the trigger 13 and passing throush a slot 16b in the sear lever 10. On pulling the trigger levers 14, 15 are raised and a projection 14b on the lever 14 engaging under the front edge 10e of the slot lOb pivots the sear lever 10 to withdraw: the sear 10a and release the firing pin. On recoii, the tip of the lever 15 is moved rearwards by the breech block against the action of a spring 20 and owing to abutment of a second projection 14a of the lever 14 against the rear edge of lever 15, the lever 14 is also moved rearwardly to disengage the projection 14b from the edge 10e thus allowing the return spring 17 to raise the sear 10a which will engage the firing nut 8 upon forward movement of the breech block even though the trigger remains pulled. The firearm is thus in cocked position for firing another shot, and in this position the sear lever 10 rests upon the outside of a spacing collar 21. In the safe position of the cam 4. a control surface 4m, Fig. 2. engages the sear lever 10 to prevent retraction of the sear 10a and thus firing of a cartridge. Fig. 4 shows the cocked position for continuous fire in which a peg 4b on the cam 4 now bears against a bevelled edge 14c on the tip of the lever 14 to move it rearwardly and the lever 15 is also moved rearwardly so that its tip is no longer in the path of the breech block. The surface 4g on the cam 4 has also moved to allow the sear 6 to move upwards under the action of its spring 23. When the trigger is pulled a pair of collars 19 on pin 16 engage the under edge of the sear 6 to retract it and release the breech block and at the same time projection 14a engaging under the rear edge 10d of the slot 10b retracts the sear 10a. The breech block moves forward to insert a live cartridge in the breech, locks the breech block proper 7a and at the same time. since the casing 7' has moved forward relative to the breech block proper 7a, releases the firing nut 8 to permit forward movement of the firing pin 11 under the action of the spring 12 and its own momentum.